Correctly forwarding system messages to a valid account

Hi all,

One of the servers we manage is not receiving system emails (i.e. emails sent from cron and the like to the 'root' account). If I manually send an email using "echo 'Hello World' | mail -s test root", I get the following entries in /var/log/mail.log:

As shown above, the email is bounced because the hostname "loops back to myself". I've tried creating an alias so that emails to "root" go to "admin@example.com" but cannot do this from the Admin web interface because it wants an "@hostname" portion with the email address, which will not match the messages the system is trying to send.

I think that the cause of the problem is that the mail server is resolving any email address such as "root" without an explicit hostname to "root@mail.example.com" instead of "root@example.com", and I note that in /opt/zimbra/postfix-2.6.5.2z/conf/main.cf the 'myhostname' entry is 'mail.example.com'. I suspect I need to change this, but am not sure (and don't want to break anything given this is a production system), and also saw elsewhere on the forum that main.cf is auto-generated and is therefore overwritten by... something.

Unfortunately, somebody else took over this problem from me, and did solve it, but I'm not sure exactly how. I think it had to do with either altering /etc/hosts, or changing the list of domains for which Zimbra will handle mail to include localhost.